What was your favorite unintended gameplay mechanism that players started using? Richard Bartle used the example of communicable diseases which players would infect entire zones with to weaken them. Does anyone here have any?

One of my favorite was on a MUD I played a long time ago. Their command parser when checking through arguments that are supposed to be objects would only check until they found the first argument, see if they could perform the requested action, and if not, fail rather than searching other objects with similar arguments.

This meant that if you had "potion of heal" and "an empty pot" in your inventory, with empty pot being the first one, quaff pot would always tell you the pot was empty or it was unquaffable.

Knowing this abusability, I had a custom item crafted that had no description in inventory, but had the alias of every healing potion in the game. In the middle of combat I would slip it into someone's inventory and essentially deny them all chances of healing. Since combat there was very heal heavy, it'd lead to a win before they even realized what happened. After that I'd just remove it from their corpse and they'd often be none the wiser.

Eventually a few imms caught on and fixed the item itself, but I still think the abusability is out there. It made for interesting PK gameplay, but required a specific setup to properly abuse.

The abusive example there makes my skin crawl; my most favorite thing in the world is the emergent behaviors that are made possible by a flexible, interoperable system, but you seem to be more talking about cheesy abuses made possible by poorly designed systems.

I think I'll respond in the spirit of what I thought the thread would be about.

One event like this that was a particular favorite of mine involved 1) a soul-sucking intelligent dagger named Soulshard, and 2) the Kazarak guild, in which your body is possessed by an incorporeal demon. The Kazarak have the ability to consume magical items to fuel themselves. Soulshard will, if hungry enough, attack less powerful wielders and do its soul-sucking routine on them instead of their enemies; you can try to unwield it when it's doing this, but it doesn't want to let you. This Kazarak wielded Soulshard and was attacked, and was failing to break free and unwield the it; in a quick bit of thinking, he consumed it instead. It was eating him, so he ate it back.

Another clever application of the Kazarak consume ability is in getting rid of gems of entrapment, which basically englobe everyone in a room so that they can't get away or be assisted; useful for PK and for isolating NPCs who have friends. Turns out that Kazarak can target the globe they're in with consume, so it's not so useful against a sufficiently alert one.

Next one involves 1) warpstones, which can randomize your race, gender, attributes, and material colors -- the color of your hair, eyes, skin, horns, fur, what-have-you, and 2) Kurd the Vivisectionist, who provides various services such as sex changes, race changes, and material color changes, using corpses sold to his mortician associate as raw materials. Now, when changing material colors, warpstones aren't limited to the naturally occurring choices; sometimes they'll change you to completely random colors and color patterns. So people hit on the idea of making alts, warping them repeatedly, getting them killed and selling their corpses to the mortician; if your eyes were warped to paisley, for example, then that meant Kurd had one set of paisley eyes he could sell. The current reigning highest-level character is a dwarf with prismatic skin, dark-brown-flecked bright red eyes, and pearly hair because of this.

The Erisian Liberation Front's guildmaster, Sinister Dexter, is imprisoned in this place called the Shadow Tower. This used to be no big thing because someone would unlock all the doors in the Shadow Tower shortly after a reboot and they'd stay that way, but a while ago the guards started actually closing doors occasionally, so it became more of an issue; the keys aren't necessarily trivial to get hold of. However... all of our guildmasters run on verbal commands, like you actually say "advance" in order to advance levels, rather than typing advance as a command or whatever. And our shout command is an actual verbal shout that carries for a few rooms, rather than a MUD-wide broadcast. So eventually people figured out that they could stand outside Sinister Dexter's cell and shout "advance" in order to go up levels.

One that's shading more toward the abusive was how it became popular to use 'tell <npc> you there?' to find out if the NPC you like to farm is alive at the moment. No longer possible. Now you at least have to use a scrying mechanism like a crystal ball or the seer psi talent.

I think you read too much into my example. I'm not really in favor of that particular example so much as I am of creating an open-ended system where players can create their own content. In that particular example, the content was generated through "bugs" in the system.

However, if that's the only tool available, should players really be chided for making use of it? The MUD in question was most enjoyable because the little abusabilities of that nature which *made* it more open ended. It was a pretty perfect example of unintended gameplay and actually lead to a lot of very creative solutions on the part of players.

Although the systems were somewhat poorly designed (it exists in all circle, and probably most Dikus that I'm aware of), they opened up the path of exploring the potential nuances of every single change or element of interaction. The command parser extended the gameplay and complexity of Player Killing even though that was not the original intention.

As a result, player killing on the MUD in question became a lot more cerebral at the higher end of things and required a lot more cunning than on most other Diku's I'd seen. It was just a coincidence that this had happened as such, but it started the idea in my head of designing for exactly these "unintended consequences" and in essence analyzing the mini-gameplay opportunities existant within each and every system I develop.

One that's shading more toward the abusive was how it became popular to use 'tell <npc> you there?' to find out if the NPC you like to farm is alive at the moment. No longer possible. Now you at least have to use a scrying mechanism like a crystal ball or the seer psi talent.

What was the original purpose of "tell <npc> you there?"? Or was it a system where you could send a tell to any npc and it would go through if they were alive? If so, that was also existent in the MUD I played, and iterating through the mobs of similar name via tell 2.mobname 3.mobname, etc was a good way of finding the exact mob you wanted to track for the tracking system.

The other examples you give though are spot on with what I was thinking with this thread. I'm actually planning an update to our races system with this sort of methodology in mind of giving them a variety of actions with wide ranging possibilities for use and letting them create their own gameplay out of it.

Giants that can lift people up and move them from room to room, but can not hurt them and can be squirmed out of. It opens up a lot of interesting gameplay, from holding an enemy at bay until your friends can escape, to taking a wounded person out of the battlefield. Seperating a team, taking the rider right off of his mount and moving him into adjacent areas. Probably a lot more that I've yet to even conceive. The pure open-endedness of such a situation is really quite interesting and will likely make for very unique gameplay upon completition.

In the original God Wars mud, demons had the ability to shapechange into powerful demonic swords. Sometimes the stronger demons would bully their weaker brethren into serving them as weapons for PK, but other than that the power was rarely used. However there was also a 'transport' command which allowed you to transport items to other players, and some of the demons discovered that they could transport each other (as swords) to any mob in the mud...including the guardians within enemy clan halls.

A more abusive variant of the above revolved around the 'preserve' spell, which was designed to let people preserve body parts as food or trophies. PK consisted of mortally wounding your opponent and then decapitating them, whereby the victim would remain as a severed head for a short while before rotting and reforming their body. Through use of the preserve spell, the players remained permanently trapped as a head until their killer quit or the mud crashed.

Some players would transport these preserved heads to random mobs around the mud, sometimes setting an ambush for the players' clan mates in case they came to the rescue. On one occasion, a player managed to single-handedly wipe out most of the mud, killing the other players one after the other and storing their preserved heads in a bag (the heads were still able to talk to each other within the bag, so at least they could plot their revenge).

In a later version of the mud, vampires were able to feed blood to humans to turn them into 'ghouls' - mortal with limited vampiric powers. One of these powers was called 'darkheart', and it allowed the vampire to rip out their own heart to render themselves immune to staking. Suffice to say that if a ghoul gained that power and used it, they died instantly.

A fun example of unintended gameplay in my current mud revolves around the combination of the alchemy crafting system (which explodes if you mess up), Inferno (a demon power which inflicts damage on everyone around you - and is particularly powerful if you use it while dead) and Soul Devourer (a talent which heals you by up to half the maximum health of those you kill). Players would blow themselves up with the alchemy set, use Inferno to shred everyone around them, and then come back to life by absorbing health from their victims.

Here are some other examples of players taking advantage of unintended gameplay:

* Werewolves have a power called 'Fang Forging' which lets them collect fangs from their victims and sew them into necklaces or bracelets. Mages have an Enchantment power that lets them add permanent bonuses to items. This combination allows werewolves to very quickly create a reasonable fang necklace or bracelet by getting a mage to enchant the fangs (although the results aren't as good as a properly forged one).

* Vampires have a power called Blood Runes that lets them draw runes on themselves. One of these runes is called Aegis, and when placed on the chest or cheeks it provides superb natural armour - but only to locations that aren't protected by worn armour. One player discovered that by breaking his armour he would remove its protection (thus allowing Aegis to kick in) while still benefiting from the other magical armour bonuses.

* Mages have spell called Burning Fury, a minor 'rage' buff. However many players favour a talent called Serenity, which gives them a variety of bonuses while not in a rage. When cast on such players, Burning Fury gave its minor bonuses at the expense of the larger Serenity bonuses - and because it was a buff, it couldn't be resisted.

* Randomly encountered mobs destroy themselves after a while if nobody is around, although quest mobs remain for the lifetime of the quest area. One quest involves killing a Witch-King, who spawns when you destroy his coffin. If you haven't killed his two guards first, they'll rise from their coffins as well, making it an extremely difficult fight. However one player discovered that he could destroy the guards' coffins, then teleport to the back of the barrow (out of their line of sight), and they'd vanish (because they were spawned by the coffins rather than initialised as quest mobs) - allowing him to take down the Witch-King without fighting the guards.

* Ocean-based mobs would sometimes drag themselves out of the water to follow their opponents. They were invariably pretty slow, making them extremely easy to pick off with ranged weapons.

* The code for calculating distances would overflow at the extreme range, resulting in a specific coordinate location that was right beside everywhere else - you could target this location and teleport or leap to it (because it was always 0 feet away), and from there you could attack (or be attacked by) anyone else in the world. This also allowed players to travel anywhere in the world with two short jumps.

What was the original purpose of "tell <npc> you there?"? Or was it a system where you could send a tell to any npc and it would go through if they were alive?

Yeah, that. The tell command used a locator function that's generic to PCs and NPCs rather than the one that's PC-specific. There was even a guild in which you could use tells to the guildmaster (Fezzik, the Brute Squad guildmaster) to do guild commands.

This became increasingly dated as we started making more distinctions between IC and OOC actions, with tell landing on the OOC side of the fence, so when I noticed people using 'tell <xpfarm> you there?', it wasn't a hard decision to make it PC-only.

I just remembered my all-time favorite abuse. Once upon a time, circa 1994 maybe, there was this player named Neuromancer of Whira who always RPed being in love with Dara the high priestess of Discordia. He was a member of the presently-defunct Rainbow Magi guild, who had powers corresponding to colors; "rainbow gold" was a rather poorly coded mind-control effect. So Neuromancer used rainbow gold on Dara and took her to the Losthaven minister to get married.

However, the marriage code checked to see if you were trying to marry an NPC, and refused on a message written vaguely as if you were trying to commit bestiality. So when he tried to marry Dara, it didn't work. So, crafty devil that he was, he ordered Dara to marry him. The marriage code only checked to see if you were trying to marry an NPC, not if you were one yourself; he fulfilled his dreams and became the first and last player ever to successfully marry Dara or any other NPC.

What got rainbow gold disabled was when the same player used it on Malaclypse the Younger, the POEE guildmaster, who was unkillable and had full POEE guild powers and unlimited SP. He certainly had fun for a while, though.

The old mud I played on (WileyMUD II) used to be a full PK mud. At level 15, wizards got the spell Energy Drain, which drained 1d4 levels from the victim if they didn't make their save. When you lost a level, you lost whatever abilities came at that level.

When my friend Muidnar became the first wizard to hit level 15, he vowed that nobody else would ever pass level 15 in the game. Sure enough, he wandered around draining anyone who was 13 or 14, to keep his monopoly of power.

The devs eventually decided to do something, and they implemented a PK registration system. Only players who were both registered could fight one another. To register, you went to the healer NPC in the newbie village and said 'register me' in the room.

Well, WileyMUD also had the ventriloquate spell, which broadcast to the room the message of your choice as if the target player had said it (assuming they failed their save).

I think you can see how certain players enjoyed standing in the room invisible and casting ventriloquate victim 'register me' whenever anyone walked through the room.

Of course, that got fixed by a making it a tell with a confirmation, but not before quite a few people became PK-enabled.

Khorne class received special Khorne-only items per level that sometimes were copies of other items already received. So, they received a Khorne Bag that allowed them to combine the items into a single stronger one...

Well, when people decided to try to take some +1/+1 swords and make a +50/+50 version, no doubt there was much rejoicing while it lasted.

Thread necro was actually a win this time. Was a good re-read Kavir, and a nice UO article. Also made me think of a few things I've seen before.

One mud I used to play had pretty complex interactions in how things worked which allowed interesting behavior, such as if someone using infravision got exposed to a fireball, they'd be blinded with almost no chance of resistance. But some mobiles had quite good magic resistance. So a few smarter players got the idea after a while that an easy way to get these guys down was to throw darkness in the room to activate the mob's infra, then fireball them for a quick blind and bash.

Other mobiles had ultravision, great in the dark, useless and even painful in normal light. A quick slap and run into daylight and the mob is blind and ticking (very minor but additive) damage.

Another nice one was the bash skill. Obviously an opponent on the ground is much easier to fight than one standing. Of course some mobiles were !bash, but if they were warrior types they'd of course try to bash you. But hey, it is a lot harder to shield bash a target that is more than one size smaller than you, so these !bash mobs, being a size larger at least, would be fought by having the tank *kneel* whenever they thought a bash might be incoming, if the bash did come, the now even SMALLER tank was almost universally missed, accomplishing the action putting the !bash mobile onto the ground facedown for a round or two.

"Players managed their own experience. We just gave them their own tools," Koster recalled, saying modern MMOs control players much more now, though granted "a huge percentage of the time" players made each other miserable.

"But when they pulled something off like the weddings, sporting events... funerals... the player governments that emerged... that's when it was really magic."